The present invention relates to a ball bearing with a high load-bearing capacity and of small size, particularly in the radial direction.
The ball bearing of the invention is of the so-called oblique type, that is to say one in which the surface of each rolling track for the balls, in axial section along any line passing through the axis of a ball, is shaped as an arc of a curve the normal to which, taken at the mid point of the curve itself, is inclined by a predetermined angle with respect to the said axis, in such a way that the direction of the forces transferred between each ball and the said track is inclined exactly by this angle with respect to the axis itself.
As is known, to increase the load-bearing capacity of a ball bearing it is necessary to increase the number of balls or their dimension; if the bearing is of the so-called fully filled type, that is to say in which the balls are substantially in contact with one another, it is not possible to increase the number of balls without increasing the diameter of the bearing and therefore, whenever it is desired to obtain such an increase of load-bearing capacity maintaining substantially unchanged the dimensions of the bearing, in particular in a radial sense, the diameter of the balls themselves must be increased. This constructional solution involves, however, having rings, in particular the outer ring, which are particularly thin; in such conditions, because of the reduced thickness of the rings, these are not able effectively to form abutments with the members on which the bearings are mounted or to which they are fixed with respect to the shaft; moreover, such very reduced thicknesses can be the cause of distortions or breakages of the rings themselves during heat treatments to which they are subjected, or whenever such rings fall during mechanical working subsequent to the heat treatment.